Lawyers familiar with US rules on patent invalidation may find some familiar parallels and some key differences in the Japanese system.

It is not uncommon for patent offices to issue defective patents. In many countries defective patents can be corrected by post-issuance reexamination procedures. In most cases this is not done by the patent office, but by the courts. Traditionally in Japan, the Japan Patent Office (JPO)had exclusive jurisdiction over patent invalidation proceedings by way of administrative oppositions and invalidity appeals.

However all of that changed in April 2000, when the Japanese Supreme Court decided in Texas Instruments vs Fujitsu that in cases where a court was hearing an infringement action, and where it concluded that it was highly likely that the patent was invalid (to the extent that the issue is fairly easy for the court to understand), the court could decline to enforce the patent, because any such enforcement would be a patent misuse. {Full Discussion}.

To discuss this topic further, or any other matter related to Japanese patent procedures and enforcement please feel free to contact the author Yoshinari Kishimoto, (ykishimoto@sughrue.com), at Sughrue Mion, PLLC in Washington DC, USA.